John Gill Commentary Genesis 20:15

"And Abimelech said, Behold, my land is before thee. Dwell where it pleaseth thee." — Genesis 20:15 (ASV)

And Abimelech said, behold, my whole land [is] before you ,
&c.] Instead of bidding him be gone, and sending him away in haste out of his country, as the king of Egypt did in a like case, he solicits his stay in it; and to encourage him to it, makes an offer of his whole kingdom to him, to choose which part of it he would to dwell in: dwell where it pleases you ;
if there was anyone part of it better than another, or more convenient for him, his family and his flocks, he was welcome to it.